CONCORD, N.H. – When a headless, limbless body was found floating in a Manchester river 13 years ago, Kelly Ayotte, then a young prosecutor, didn’t flinch from the gruesome investigation. She tracked down a witness living in a tent and accompanied police the night they interviewed him.

“She came out in a skirt and high heels when we got to the location and actually joined us through the muck, the woods and the branches,” said Manchester Capt. Nick Willard. “My first impression of her was, ‘Here is somebody that is going to go above and beyond her duty to see to it that the job is done.’ “

Ayotte, now a U.S. senator, has raised her profile in recent months on the national level. Her name was in the mix as a possible running mate for Republican presidential hopeful Mitt Romney, much to the delight of her home-state supporters. Romney announced Saturday that he had chosen Wisconsin Rep. Paul Ryan as his vice-presidential candidate.

Ayotte said in a statement Saturday that Ryan was a “fantastic choice.”

For now, Ayotte will continue to focus on her job in the Senate, but it’s possible Romney may call on her should he win the presidency, one congressman surmised.

“We’re happy that she’s going to remain in the Senate and focus on the fiscal responsibility issues that we need focusing on,” Rep. Frank Guinta of New Hampshire told WMUR-TV on Saturday. “… Kelly will continue to serve as a senator, and who knows, she could serve in a Romney Cabinet. But we’re very pleased that ultimately Paul was the choice and, and happy to have Kelly as my colleague.”

Romney and Ayotte have developed a warm relationship. She’s often at his side when he visits New Hampshire and Romney has been impressed by her political savvy and understanding of her state. He sees her as a trusted member of his campaign and has encouraged aides to use her as much as possible, especially to warm female voters to Romney’s camp.

She also is someone who understands a range of issues from her time as attorney general, from banking to health care.

“She is really impressive at getting herself prepared, whether it’s to argue before the Supreme Court, which she did on behalf of New Hampshire,” said former House Speaker Donna Sytek. “… She’s just very determined to do what she needs to do to get the job done. I’ve been very impressed at how she’s done that at each step of her career.”

Attorney Jack Middleton, who worked with Ayotte at Manchester’s McLane law firm before she joined the attorney general’s office in 1998, described her as bright, capable and organized.

“She’s also a very warm human being and I think people who get to know her really like and appreciate her,” he said.

Ayotte grew up in Nashua, where she now lives with her husband and two children. She returned to New Hampshire after law school and clerked for a state Supreme Court judge before becoming a defense attorney and then prosecutor. She was the first woman to serve as the state’s attorney general.

Willard worked closely with Ayotte in 2006, when she sought and won the death penalty against a man accused of killing a Manchester police officer. He said Ayotte felt compelled to take a lead role in the prosecution given that a man’s life was at stake.

“She has the ability to be strong and offer direction firmly when needed, but she also has the compassion to do it in such a way that all you want to do is work for Kelly,” he said. “She’s the type of person that leads without trying to lead.”